title: Purification, cDNA cloning and expression of 15-oxoprostaglandin 13-reductase from pig lung.
abstract: 15-Oxoprostaglandin 13-reductase (PGR) has been purified to apparent homogeneity from pig lung. The enzyme was estimated to have a molecular mass of 36 kDa by both SDS/PAGE and non-denaturing PAGE, indicating that the enzyme is a monomer. 15-Oxo-PGE1, 15-oxo-PGE2 and 15-oxo-PGF2alpha were found to be substrates for the enzyme, whereas the corresponding 15-hydroxyprostaglandins were not. The reverse reaction, the oxidation of 13,14-dihydro-15-oxo-PGE1 to 15-oxo-PGE1, was not observed. Either NADH or NADPH could serve as a coenzyme. However, the Vmax with NADH was approx. 3-fold that with NADPH, while the Km for NADPH was approx. one-tenth that for NADH. Cloning of the cDNA was achieved by PCR and library screening. A 600 bp PCR product containing the sequences of three different tryptic peptides derived from purified PGR was used for cDNA library screening by plaque hybridization. A cDNA clone that contained the entire PGR coding sequence of 987 bp was obtained. The sequence codes for a protein of 329 amino acid residues with a calculated molecular mass of 35791 Da. Homology analysis indicated that the sequence is virtually identical with that of leukotriene B4 (LTB4) 12-hydroxydehydrogenase [Yokomizo, Ogawa, Uozumi, Kume, Izumi and Shimizu (1996) J. Biol. Chem. 271, 2844-2850]. Expression of this cDNA in Escherichia coli resulted in a protein exhibiting both PGR and LTB4 12-hydroxydehydrogenase activities. However, the specific activity of PGR with 15-oxo-PGE1 as a substrate was approx. 300-fold that of LTB4 12-hydroxydehydrogenase. These results indicate that the cloned cDNA codes for a protein with two different enzyme activities, with 15-oxoprostaglandins as the preferred substrates.
authors.affiliation: Division of Medicinal Chemistry and Pharmaceutics, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0082, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Ensor
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: H H
authors.initials: HH
authors.lastname: Tai
mesh_terms: D011452:15-Oxoprostaglandin 13-Reductase / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D007158:Immunologic Techniques; D007700:Kinetics; D008168:Lung / Q000201:enzymology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013552:Swine
chemical_list: D018076:DNA, Complementary; D011994:Recombinant Proteins; D011452:15-Oxoprostaglandin 13-Reductase